The present disclosure relates to wireless communication systems, and more particularly, to a method and a base station for operating in accordance with a wireless communication protocol.
A wireless communication system is a complex network of systems and elements. Typical systems and elements include (1) a radio link to mobile stations (e.g., a cellular telephone or a subscriber equipment used to access the wireless communication system), which is usually provided by at least one and typically several base stations, (2) communication links between the base stations, (3) a controller, typically one or more base station controllers or centralized base station controllers (BSC/CBSC), to control communication between and to manage the operation and interaction of the base stations, (4) a switching system, typically including a mobile switching center (MSC), to perform call processing within the system, and (5) a link to the land line, i.e., the public switch telephone network (PSTN) or the integrated services digital network (ISDN).
A base station subsystem (BSS) or a radio access network (RAN), which typically includes one or more base station controllers and a plurality of base stations, provides all of the radio-related functions. The base station controller provides all the control functions and physical links between the switching system and the base stations. The base station controller is also a high-capacity switch that provides functions such as handover, cell configuration, and control of radio frequency (RF) power levels in the base stations.
The base station handles the radio interface to the mobile station. The base station includes the radio equipment (transceivers, antennas, amplifiers, etc.) needed to service each communication cell in the system. A group of base stations is controlled by a base station controller. Thus, the base station controller operates in conjunction with the base station as part of the base station subsystem to provide the mobile station with real-time voice, data, and multimedia services (e.g., a call).
After a call is initiated in an original cell, the mobile station may continue to scan the neighboring cells to determine if the signal from another cell becomes comparable to that of the original cell. When this happens, the switching system (e.g., MSC) indicates to the mobile station that the call has entered a new cell""s coverage area and that a handoff can be initiated. The mobile station transmits a control message to the MSC, which states that the new cell site is now strong and identifies the new cell. The MSC initiates the handoff by establishing a link to the mobile station through the new cell while maintaining the old link. While the mobile station is locate in the transition region between the two cells, the call is supported by communication through both cells; thereby eliminating the ping-pong effect (i.e., repeated requests to hand the call back and forth between cells). The original cell site will only discontinue handling the call when the mobile station is firmly established in the new cell.
The cells may operate in accordance with a variety of wireless communication standards. For example, the original cell may be operable in accordance with the code division multiple access (CDMA) 2000-1X standard while the new cell may be operable in accordance with either the CDMA 2000-1X standard or the CDMA 1X-EV/DV standard. The CDMA 2000-1X standard provides wireless data packet services at 144 kilobits-per-second (kbps) whereas the CDMA 1X-EV/DV standard may provide real time voice, data, and multimedia services on a single radio frequency carrier with existing CDMA 2000 networks at data rates up to 3.07 megabits-per-second (Mbps). With the enhanced data rates provided by CDMA 1X-EV/DV standard, a user may browse the Internet, access e-mail, or transmit/receive large data files or images via a mobile station (e.g., a cellular telephone) with a wireless communication link as if the user accessed the Internet via a laptop or a desktop computer with a wired Internet connection. Further, the CDMA 1X-EV/DV may be backward compatible with other CDMA components such as IS-95A and IS-95B components. Thus, it may desirable to use the CDMA 1X-EV/DV standard when all possible.
One aspect of designing a wireless communication system is to optimize the resources available to the wireless communication system. For example, a mobile station should operate in accordance with the CDMA 1X-EV/DV standard when available because the CDMA 1X-EV/DV standard provides higher data rates and greater data capacity than the CDMA 1X standard. Therefore, a need exist to optimize communication resources by operating in accordance with the CDMA 1X-EV/DV standard.